Hydrocarbons can be produced through a wellbore traversing a subterranean formation. The wellbore can be relatively complex in that it can include various zones defined by zonal isolation devices. Completion and production in each zone can be configured and controlled independent of other zones. Each zone can also include one or more downhole electrical loads (or tools) that operate using electric power. Examples of these loads include pumps, solenoid operated valves, and motors.
Electric power can be delivered to these loads through cables or other types of conducting paths. A tubing encapsulated conductor (“TEC”) can be used that includes three conductors surrounded by a sheath. Because the wellbore can be long—requiring a long cable—the TEC is used with diodes downhole to control power to up to twelve different downhole loads, instead of using two cables per load, which increases costs. For example, one downhole load can receive full power independent of other loads, by applying voltage to one of the conducting paths or to the sheath, grounding another one of the conducting paths (or the sheath if applicable), and leaving the remaining conducting paths (or remaining path and sheath if applicable) floating electrically.
Although the one load receives power to operate fully independent of the remaining loads through this implementation, one or more leak paths can be present through which current can flow away from the one load in full operation. For example, in an implementation of twelve independent loads that have a similar resistive value, (i) one half of the power provided down the conducting paths is supplied to the one load intended to be powered, (ii) one quarter of the power is supplied through a second path in which two loads are between positive voltage and ground, and (iii) one quarter of the power is supplied through a third path in which another two loads are between positive voltage and ground.
Thus, the leak paths can waste half of the power that is supplied downhole and the leak paths can result in the loads in the leak paths being provided only part of the power that the loads require to operate fully. Providing part of the power to the loads can cause some loads (e.g. a motor or a pump) to operate partially when such operation is not desirable. Furthermore, certain loads may require different power levels to operate such that a load in a leak path operates fully when such operation is not desirable.
Therefore, systems and methods are desirable that can reduce or eliminate loads receiving current through leak paths or other undesirable ways in a downhole setting.